Improvement in shades for try-squares



C. B. HOPKINS SHADES F011 TRY-SQUARES. No. 189,737. Patented April 17,1877.

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CHARLES B. HOPKINS, OF TOPEKA, KANSAS.

IMPROVEMENT IN SHADES FOR TRY-SQUARES.

Specification forming part of Letters Patent No. 189,737, dated April17, 1877; application filed March 13, 1877.

To all whom it may concern Be it known that I, CHARLES P. HOPKINS,

of Topeka, in the county of Shawnee and State of Kansas, have inventedcertain Improvements in Shades for Try-Squares, of which the followingis a specification My invention consists of a shade constructed so as tobe attached to the blades of try-squares,for the purpose of renderingthem more effective in use, as hereinafter more fully described.

Figure 1 is a perspective view, showing the shade as applied in use;Fig. 2 is a plan view of the shade detached.

As is well known, try-squares are used to ascertain whether the surfacesand angles of boards and similar articles are true, and to show whereinthey are defective, in order to know how and where alteration isrequired to render them true and accurate. For ordinary work thetry-square as generally used may suffice; but where it is desired to dovery accurate work, and make perfect joints, my invention will be foundspecially useful.

The ordinary method of using a try-square is to apply it to the stick orarticle as represented in Fig. l, and then to sight with the eye alongthe edge of the piece to which the bladeA is applied, and, by observingthe point at which the light shines through between the edge of theblade and the surface on which it rests, ascertain which side or edge ofsaid surface is too low, and where it requires to be planed off torender it true. In doing this it is usual to place the article B, if asmall one, so that the square will be between the eye of the operatorand the light, in order thatthe latter may more, readily shine throughthe space or crevice between the edge of the blade and of the strip B.If the article be a large or long one, it is not convenient always to dothis; and, moreover, it frequently happens that the workman is solocated in a shop, that he cannot conveniently do it, even if thearticle be a small one. Besides this, the surrounding light, strikingupon the edge of the article, and the side of the blade toward the eye,tends to destroy the eii'ect of the small amount of light which shinesthrough the exceedingly small space under the edge of the blade, therebyneutralizing its effect, and rendering the operation incomplete.

To counteract this effect, I provide a shade, G, which I attach to theblade as represented in Fig. 1, so as to shade the edge of the strip B,where the blade of the square rests upon it, which has the effect ofrendering the rays of light which pass through between the edge of theblade A and of the strip B much more apparent or visible, and thusenable the workman to detect any error in the accuracy of the surfacesor their angles.

As represented in the drawings, this shade 0 may consist ofa piece ofsheet metal, having one edge turned up to form a flange, o, with a thinflat spring, 0, secured at one end thereto, the space between the riband the spring being such as to permit the blade of the square to beshoved therein, as shown in Fig. l, the spring clasping or pressingagainst the blade with sufficient force to hold the shade Gin place onthe blade.

It will thus be seen that the shade can readily be adjusted at anyangle, and in any position required. By placing it at an angle of fortyor forty-five degrees, as represented in Fig. 1, it will shut 011 therays of light falling from above, and also from the right-hand side,thus shading the point of contact between the edge of the blade and ofthe strip, and thereby greatly increasing the effect of the rays oflight passing through between the blade and the strip B.

It is obvious that, if desired, the shade may be varied in form; as, forinstance, it may have its top extended and bent over so as to make acover at the top. So, too, its front edge may be bent inward, ifdesired, or it may be made concave, these and similar variations in formbeing mere modifications, to be adopted or not, as may be desired.

It is also obvious that, instead of the springolamp, a thumb-screw maybe used to fasten the shade to the blade; but I prefer the spring, asbeing the simplest and easiest to use.

This invention is especially useful in all cases where nice joints arerequired, as in the better class of cabinet and carpenter work. It isalso useful in ordinary carpenter-work,

2. The shade 0, provided with the springclamp, c, or equivalent device,for attaching it to the blade of a try-square, substantially as, and forthe purpose set forth.

CHARLES B. HOPKINS.

Witnesses CHARLES B. SMITH,

ELms SKULL.

